Employee Benefits - Summary of Equity-Based Awards for Employees (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Awards
Share-based awards granted (in shares)	100,000	200,000	100,000
Common Stock Awards
Awards
Nonvested common stock awards, Beginning balance (in shares)	231,280
Granted (in shares)	55,815
Vested (in shares)	(84,641)
Forfeited/Cancelled (in shares)	(3,101)
Nonvested common stock awards, Ending balance (in shares)	199,353	231,280
Weighted Average Grant Date Fair Value Per Share
Nonvested common stock awards, Beginning balance (in USD per share)	$ 48.05
Granted (in USD per share)	124.88
Vested (in USD per share)	48.87
Forfeited/Cancelled (in USD per share)	62.36
Nonvested common stock awards, Ending balance (in USD per share)	$ 68.99	$ 48.05
Performance-Based Stock Awards
Awards
Nonvested performance-based stock awards/units, Beginning balance (in shares)	166,961
Share-based awards granted (in shares)	42,449
Vested (in shares)	(64,525)
Forfeited/Cancelled (in shares)	(1,484)
Nonvested performance-based stock awards/units, Ending balance (in shares)	143,401	166,961
Weighted Average Grant Date Fair Value Per Share
Nonvested performance-based stock awards/units, Beginning balance (in USD per share)	$ 59.97
Granted (in USD per share)	123.32
Vested (in USD per share)	52.79
Forfeited/Cancelled (in USD per share)	123.26
Nonvested performance-based stock awards/units, Ending balance (in USD per share)	$ 81.30	$ 59.97
Performance-Based Restricted Stock Units
Awards
Nonvested performance-based stock awards/units, Beginning balance (in shares)	13,273
Share-based awards granted (in shares)	8,470
Vested (in shares)	(12,952)
Forfeited/Cancelled (in shares)	(539)
Nonvested performance-based stock awards/units, Ending balance (in shares)	8,252	13,273
Weighted Average Grant Date Fair Value Per Share
Nonvested performance-based stock awards/units, Beginning balance (in USD per share)	$ 36.51
Granted (in USD per share)	126.89
Vested (in USD per share)	36.51
Forfeited/Cancelled (in USD per share)	73.06
Nonvested performance-based stock awards/units, Ending balance (in USD per share)	$ 126.89	$ 36.51